Emerald Glass Frogs are among the most common Glass Frog species in Costa Rica. These lovely little frogs are found throughout most of the country, excluding the Guanacaste region and mountain peaks higher than 2000 meters above sea level.

Like all other Glass Frogs, Emerald Glass Frogs are quite small and have a maximum total length of 31 millimeters.

When looking at an Emerald Glass Frog  from beneath, one can easily observe the frog's digestive tract.

The intestines are also transparent, so anything present in the intestines is also visible through the skin. The upper part of the Emerald Glass Frog's underbody is covered with a white parietal peritoneum, but the bluish-green bones are clearly visible as well as the red ventral vein.

Emerald Glass Frogs are quite unique among other Glass Frogs found in Drake Bay. Males have humeral spines which protrude from the frog's upper arms. The lack of humeral spines on the individual photographed on this page indicates that it is a female frog.

The male frog's humeral spines are probably used while mating with females and in combat with other male frogs. Male Emerald Glass Frogs are very territorial and have been observed engaging in wrestling matches which may last for over an hour!

During these battles, the tiny warriors hang upside down by their toes from the bottom of leaves. The frogs lock up in sumo style grips and wrestle until the loser drops from the fight site. The loser then shows his submission by flattening his body against the leaf litter and then must humbly flee the arena.

When attempting to attract a mate, male Emerald Glass Frogs typically call from the top of leaves in the vegetation surrounding fast moving streams.

Males may be found calling as high as five meters above the stream.

If a female is drawn to a specific male, she will join him on his roost and they will mate there. Female Emerald Glass Frogs usually lay between 25 and 40 eggs in a clear jelly. The eggs overhang the stream and hatch within 13 to 17 days.

Once the tadpoles hatch from the egg mass, they drop into the stream and finish their development there. Metamorphosis may take several months.

Emerald Glass Frogs may be found from Eastern Honduras and North-central Nicaragua to Ecuador and Colombia.

References:

Kubicki, B.  2007  Costa Rica Glass Frogs  Editorial INBio

Savage, J.  2002  The Amphibians and Reptiles of Costa Rica   University of Chicago Press